As pointed out in another section of this report the radiations from
the nuclear explosions which caused injuries to persons were primarily
those experienced within the first second after the explosion; a few
may have occurred later, but all occurred in the first minute. The
other two general types of radiation, viz., radiation from scattered
fission products and induced radioactivity from objects near the center
of explosion, were definitely proved not to have caused any casualties.
The proper designation of radiation injuries is somewhat difficult.
Probably the two most direct designations are radiation injury and
gamma ray injury. The former term is not entirely suitable in that it
does not define the type of radiation as ionizing and allows possible
confusion with other types of radiation (e.g., infra-red). The
objection to the latter term is that it limits the ionizing radiation
to gamma rays, which were undoubtedly the most important; but the
possible contribution of neutron and even beta rays to the biological
effects cannot be entirely ignored. Radiation injury has the advantage
of custom, since it is generally understood in medicine to refer to
X-ray effect as distinguished from the effects of actinic radiation.
Accordingly, radiation injury is used in this report to mean injury due
only to ionizing radiation.
According to Japanese observations, the early symptons in patients
suffering from radiation injury closely resembled the symptons observed
in patients receiving intensive roentgen therapy, as well as those
observed in experimental animals receiving large doses of X-rays. The
important symptoms reported by the Japanese and observed by American
authorities were epilation (lose of hair), petechiae (bleeding into the
skin), and other hemorrhagic manifestations, oropharyngeal lesions
(inflammation of the mouth and throat), vomiting, diarrhea, and fever.
Epilation was one of the most spectacular and obvious findings. The
appearance of the epilated patient was typical. The crown was involved
more than the sides, and in many instances the resemblance to a monk's
tonsure was striking. In extreme cases the hair was totally lost. In
some cases, re-growth of hair had begun by the time patients were seen
50 days after the bombing. Curiously, epilation of hair other than
that of the scalp was extremely unusual.
Petechiae and other hemorrhagic manifestations were striking findings.
Bleeding began usually from the gums and in the more seriously affected
was soon evident from every possible source. Petechiae appeared on the
limbs and on pressure points. Large ecchymoses (hemorrhages under the
skin) developed about needle punctures, and wounds partially healed
broke down and bled freely. Retinal hemorrhages occurred in many of
the patients. The bleeding time and the coagulation time were
prolonged. The platelets (coagulation of the blood) were
characteristically reduced in numbers.
Nausea and vomiting appearing within a few hours after the explosion
was reported frequently by the Japanese. This usually had subsided by
the following morning, although occasionally it continued for two or
three days. Vomiting was not infrequently reported and observed during
the course of the later symptoms, although at these times it generally
appeared to be related to other manifestation of systemic reactions
associated with infection.
Diarrhea of varying degrees of severity was reported and observed. In
the more severe cases, it was frequently bloody. For reasons which are
not yet clear, the diarrhea in some cases was very persistent.
Lesions of the gums, and the oral mucous membrane, and the throat were
observed. The affected areas became deep red, then violacious in
color; and in many instances ulcerations and necrosis (breakdown of
tissue) followed. Blood counts done and recorded by the Japanese, as
well as counts done by the Manhattan Engineer District Group, on such
patients regularly showed leucopenia (low-white blood cell count). In
extreme cases the white blood cell count was below 1,000 (normal count
is around 7,000). In association with the leucopenia and the
oropharyngeal lesions, a variety of other infective processes were
seen. Wounds and burns which were healing adequately suppurated and
serious necrosis occurred. At the same time, similar ulcerations were
observed in the larynx, bowels, and in females, the gentalia. Fever
usually accompanied these lesions.
Eye injuries produced by the atomic bombings in both cities were the
subject of special investigations. The usual types of mechanical
injuries were seen. In addition, lesions consisting of retinal
hemorrhage and exudation were observed and 75% of the patients showing
them had other signs of radiation injury.
The progress of radiation disease of various degrees of severity is
shown in the following table:
Summary of Radiation Injury
Clinical Symptoms and Findings
Day
after
Explo-
sion Most Severe Moderately Severe Mild
1. 1. Nausea and vomiting 1. Nausea and vomiting
2. after 1-2 hours. after 1-2 hours.
3. NO DEFINITE SYMPTOMS
4.
5. 2. Diarrhea
6. 3. Vomiting NO DEFINITE SYMPTOMS
7. 4. Inflammation of the
mouth and throat
8. 5. Fever
9. 6. Rapid emaciation
10. Death NO DEFINITE SYMPTOMS
11. (Mortality probably 2. Beginning epilation.
12. 100%)
13.
14.
15.
16.
17.
18. 3. Loss of appetite
19. and general malaise. 1. Epilation
20. 4. Fever. 2. Loss of appetite
21. 5. Severe inflammation and malaise.
22. of the mouth and throat 3. Sore throat.
23. 4. Pallor.
24. 5. Petechiae
25. 6. Diarrhea
26. 7. Moderate emacia-
27. 6. Pallor. tion.
28. 7. Petechiae, diarrhea
29. and nose bleeds (Recovery unless com-
30. plicated by previous
31. 8. Rapid emaciation poor health or
Death super-imposed in-
(Mortality probably 50%) juries or infec-
tion).
It was concluded that persons exposed to the bombs at the time of
detonation did show effects from ionizing radiation and that some of
these patients, otherwise uninjured, died. Deaths from radiation began
about a week after exposure and reached a peak in 3 to 4 weeks. They
practically ceased to occur after 7 to 8 weeks.
Treatment of the burns and other physical injuries was carried out by
the Japanese by orthodox methods. Treatment of radiation effects by
them included general supportative measures such as rest and high
vitamin and caloric diets. Liver and calcium preparations were
administered by injection and blood transfusions were used to combat
hemorrhage. Special vitamin preparations and other special drugs used
in the treatment of similar medical conditions were used by American
Army Medical Corps officers after their arrival. Although the general
measures instituted were of some benefit no definite effect of any of
the specific measures on the course of the disease could be
demonstrated. The use of sulfonamide drugs by the Japanese and
particularly of penicillin by the American physicians after their
arrival undoubtedly helped control the infections and they appear to be
the single important type of treatment which may have effectively
altered the earlier course of these patients.
One of the most important tasks assigned to the mission which
investigated the effects of the bombing was that of determining if the
radiation effects were all due to the instantaneous discharges at the
time of the explosion, or if people were being harmed in addition from
persistent radioactivity. This question was investigated from two
points of view. Direct measurements of persistent radioactivity were
made at the time of the investigation. From these measurements,
calculations were made of the graded radiation dosages, i.e., the total
amount of radiation which could have been absorbed by any person.
These calculations showed that the highest dosage which would have been
received from persistent radioactivity at Hiroshima was between 6 and
25 roentgens of gamma radiation; the highest in the Nagasaki Area was
between 30 and 110 roentgens of gamma radiation. The latter figure
does not refer to the city itself, but to a localized area in the
Nishiyama District. In interpreting these findings it must be
understood that to get these dosages, one would have had to remain at
the point of highest radioactivity for 6 weeks continuously, from the
first hour after the bombing. It is apparent therefore that insofar as
could be determined at Hiroshima and Nagasaki, the residual radiation
alone could not have been detrimental to the health of persons entering
and living in the bombed areas after the explosion.
The second approach to this question was to determine if any persons
not in the city at the time of the explosion, but coming in immediately
afterwards exhibited any symptoms or findings which might have been due
to persistence induced radioactivity. By the time of the arrival of
the Manhattan Engineer District group, several Japanese studies had
been done on such persons. None of the persons examined in any of
these studies showed any symptoms which could be attributed to
radiation, and their actual blood cell counts were consistently within
the normal range. Throughout the period of the Manhattan Engineer
District investigation, Japanese doctors and patients were repeatedly
requested to bring to them any patients who they thought might be
examples of persons harmed from persistent radioactivity. No such
subjects were found.
It was concluded therefore as a result of these findings and lack of
findings, that although a measurable quantity of induced radioactivity
was found, it had not been sufficient to cause any harm to persons
living in the two cities after the bombings.